sameeksha-Embedded-System presentation1

8/7/2019 sameeksha-Embedded-System presentation1

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Presentation

OnSummer Training Project Report

titled asEMBEDDED SYSTEMS

BySAMEEKSHA RUSTAGI

O7-ECE-197


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EMBEDDED SYSTEMS

Embedded systems are combination of computerH/W and S/W, and perhaps additional mechanicalor other parts, which are designed usingmicroprocessor or microcontroller but for a specifictask to perform a dedicated function.

In some cases, ES may be part of a larger system

One of the critical needs of embedded system is todecrease power consumptions and space whichcan be done by integrating more functions on theCPU chip


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EMBEDDED SYSTEMS

ES generally use microcontroller thatcontains many functions of computer ona single device

Motorola and Intel make some of themost popular microcontrollers

Contrast this with a Pentium based PC

which cannot be regarded as anembedded system as it is used toperform multiple tasks


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EMBEDDED SYSTEM

DEVICES PLANT CONTROL

Robots

Industrial Process controlAirplane control System

Missile Guidance System

AUTOMOTIVE

Engine Controller

Anti-brake lock controller

CONSUMER ELECTRONICS

Microwave Ovens

Digital Cameras

DVD Player

Washing Machine

TELECOMMUNICATIONSwitches

Cellular Phones


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Percentage share of various verticals inEmbedded Software market


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VARIOUS MICROCONTROLLERS

1) 8031 MICROCONTROLLER

It is an Intel product

It is an 8 bit microcontroller

Internally no ROM is provided

2)8051 MICROCONTROLLER

It is the 1st complete 8 bit microcontroller It has the same instruction set, pin configuration and

architecture, only the memory storage capacity is different

Internally PROM is provided so it is called one timeprogrammable (OTP)

3)AT89C51 MICROCONTROLLER

It is an Atmel product

It is an 8 bit microcontroller.

Internally EPROM is provided

It is multiple time programmable (MTP) i.e app 1000 times

Hence it is better than 8051 microcontroller


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Some features that make 8051 popular

8-bit data bus

16-bit address bus

34 general purpose registers each of8 bits

16 bit timers (usually 2, but may have more, orless).

3 internal and 2 external interrupts.

Bit as well as byte addressable RAM area of16 bytes.

Four8-bit ports, (short models have two 8-bitports).

16-bit program counter and data pointer

Internal RAM of 128 bytes

Internal ROM of 4Kb


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PIN DIAGRAM OF 8051


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On chip memory


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It has four parts on which it can be explained :

Register banks- R0,R1,R2 and R4are basically used to manipulate data from one memory to another memory

place.

BIT MEMORY

gives the user the ability to access a number ofbit variables.

There are 128 bit variables available to the user, numbered 00h through 7Fh

GENERAL PURPOSE REGISTERSuse to store memory addresses and data

SPECIAL FUNCTION REGISTER(SFR)

Special Function Registers (SFRs) are areas of memory that control specificfunctionality of the 8051 processor . Four SFRs permit access to the 8051s 32

input/output lines .


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SFR


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VARIOUS REGISTERS

1) A Register (Accumulator)

Its a general purpose register used for

storing intermediate results during operation

2) B Register

It is used in multiply and divide operations which areperformed only upon nos stored in A & B registers. All other

instructions use it as a spare accumulator3) R Registers (R0 to R7)

its a common name for 8 general purpose registers whichare stored in 4 banks in the scope of RAM

4) PSW Registers (program status word)

It is one of the most imp SFR which contains several statusbits that reflect the current state of the CPU. It contains carry bit,auxiliary carry, 2 register bank select bits, overflow flag, paritybit and status flag

4) DPTR Register ( data pointer)

Its used for storing data and results that have nothing to dowith memory locations

5) SP Register

It is used to point to a valid RAM address and permits stackavailability


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TIMER

The 8051 comes equipped with two timers, both of

which may be controlled, set, read,

and configured individually. The 8051 timers havethree general functions:

1) Keeping time and/or calculating the amount of time

between events,

2) Counting the events themselves,

3) Generating baud rates for the serial port.


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Timer SFRs

The805

1 has two timers which each function essentiallythe same way. One timer is TIMER0 and the other is

TIMER1.

The two timers share two SFRs

(TMOD and TCON) which control the timers.

Each timer also has two SFRs, dedicated solely to itself

(TH0/TL0 and TH1/TL1).


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Timer SFRS


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TIMER MODES


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TMOD SFRS


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TCON SFRS


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Interrupt

An interrupt is some event which interrupts normal

program execution

Interrupts give us a mechanism to put on hold the

normal program flow, execute a subroutine, and thenresume normal program flow as if we had never left it

Subroutine called an interrupt handler, is only

executed when a certain even occurs.


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8051 Microcontroller Interrupts

There are five interrupt sources for the805

1, whichmeans that they can recognize 5 different event that can

interrupt regular program execution.

Event may be one of the timersoverflowing,receiving a

character via the serial port,trasmitting a character via

the serial port or one of the two external events

Each interrupt can be enabled or disabled by setting bits

in the IE register. Also, as seen from the picture below

the whole interrupt system can be disabled by clearing

bit EA from the same register.


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IE SFR


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INTERRUPT HANDLING


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SERIAL INPUT/OUTPUT PORT

One of the 8051s many powerful features is its integrated UART,otherwise known as a serial port. The fact that the 8051 has anintegrated serial port means that you may very easily read and writevalues to the serial port. If it were not for the integrated serial port,writing a byte to a serial line would be a rather tedious processrequiring turning on and off one of the I/O lines in rapid succession

to properly "clock out" each individual bit ,including start bits, stopbits, and parity bits. However, we do not have to do this. Instead, wesimply need to configure the serial ports operation mode and baudrate. Once configured, all we have to do is write to an SFR to write avalue to the serial port or read the same SFR to read a value fromthe serial port.

The 8051 will automatically let us know when it has finished sending

the character we wrote and will also let us know whenever it hasreceived a byte so that we can process it. We do not have to worryabout transmission at the bit level--which saves us quite a bit ofcoding and processing time.


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SCON SFR


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THANK YOU

BY SAMEEKSHA RUSTAGI

Documents

sameeksha-Embedded-System presentation1